The invention relates in general to fuel injection systems and in particular to fuel injection systems for handling high vapor pressure liquid fuel.
A problem with high pressure fuel injection systems is supplying each fuel injection valve with enough liquid fuel to insure reliable engine starting. One aspect of the problem is the presence of vapor bubbles in the injectors. The vapor bubbles must be flushed out and replaced with liquid fuel for reliable engine starting. The problem is more severe in a hot-start condition wherein fuel is present in vapor form in the fuel lines and in the individual fuel injection valves. The vapor bubbles must be rapidly flushed out from the injectors and the injectors cooled down.
The present invention provides a fuel injection system comprising at least two fuel injectors; each fuel injector including at least one fuel inlet and at least one vapor outlet, the at least one vapor outlet being located vertically higher than the at least one fuel inlet; at least two pods, one fuel injector being inserted in each pod, respectively; each pod including a fuel inlet connection in fluid communication with the at least one fuel inlet of the injector and a fuel return connection in fluid communication with the at least one vapor outlet of the injector, the fuel return connection being located vertically higher than the fuel inlet connection; a fuel supply line connected to the fuel inlet connection of each of the pods and a fuel return line connected to the fuel return connection of each of the pods such that the pods with the injectors inserted therein are connected in a parallel arrangement.
In the fuel injection system, each of the at least two injectors includes internal passageways fluidly communicating the at least one fuel inlet of the injector with the at least one vapor outlet of the injector. Preferably, an internal surface of each pod and an external surface of an injector inserted in the pod define a fluid passageway between the fuel inlet connection of the pod and the fuel return connection of the pod wherein the fluid passageway is external to the injector.
Further objects, features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the following drawing.